Support setting command in go-getter plugin

This allows one to use non-kustomization remote source

plugin/someteam.example.com/v1/gogetter/GoGetter

@@ -11,7 +11,8 @@
 #  metadata:
 #    name: example
 #  url: github.com/kustless/kustomize-examples.git
-#  # overlay: base  # (optional) relative path in the package
+#  # subPath: base # (optional) relative path in the package
+#  # command: cat *.yaml # (optional) build command, default `kustomize build $subPath`
 #
 # download kustomize layes and build it to stdout
 #
@@ -20,7 +21,7 @@
 #
 # TODO: cache downloads
 
-set -e
+set -ex
 
 # YAML parsing function borrowed from ChartInflator
 function parseYaml {
@@ -32,7 +33,8 @@ function parseYaml {
     local t=${v#"${v%%[![:space:]]*}"}  # trim leading space
 
     if [ "$k" == "url" ]; then url=$t
-    elif [ "$k" == "overlay" ]; then overlay=$t
+    elif [ "$k" == "subPath" ]; then subPath=$t
+    elif [ "$k" == "command" ]; then command=$t
     fi
   done <"$file"
 }
@@ -40,7 +42,13 @@ function parseYaml {
 TMP_DIR=$(mktemp -d)
 
 parseYaml $1
+
+if [ -z "$command" ]; then
+  command="kustomize build"
+fi
+
 go-getter $url $TMP_DIR/got 2> /dev/null
-kustomize build $TMP_DIR/got/$overlay
+
+(cd $TMP_DIR/got/$subPath; $command)
 
 /bin/rm -rf $TMP_DIR

plugin/someteam.example.com/v1/gogetter/GoGetter_test.go

@@ -30,7 +30,7 @@ apiVersion: someteam.example.com/v1
 kind: GoGetter
 metadata:
   name: example
-url: github.com/kustless/kustomize-examples.git
+url: github.com/kustless/kustomize-examples.git?ref=adef0a8
 `)
 
 	th.AssertActualEqualsExpected(m, `
@@ -40,6 +40,66 @@ data:
   enableRisky: "false"
 kind: ConfigMap
 metadata:
-  name: the-map
+  name: remote-cm
+`)
+}
+
+func TestGoGetterCommand(t *testing.T) {
+	tc := plugins_test.NewEnvForTest(t).Set()
+	defer tc.Reset()
+
+	tc.BuildExecPlugin(
+		"someteam.example.com", "v1", "GoGetter")
+
+	th := kusttest_test.NewKustTestPluginHarness(t, "/app")
+
+	m := th.LoadAndRunGenerator(`
+apiVersion: someteam.example.com/v1
+kind: GoGetter
+metadata:
+  name: example
+url: github.com/kustless/kustomize-examples.git?ref=adef0a8
+command: cat resources.yaml
+`)
+
+	th.AssertActualEqualsExpected(m, `
+apiVersion: v1
+data:
+  altGreeting: Good Morning!
+  enableRisky: "false"
+kind: ConfigMap
+metadata:
+  name: cm
+`)
+}
+
+
+func TestGoGetterSubPath(t *testing.T) {
+	tc := plugins_test.NewEnvForTest(t).Set()
+	defer tc.Reset()
+
+	tc.BuildExecPlugin(
+		"someteam.example.com", "v1", "GoGetter")
+
+	th := kusttest_test.NewKustTestPluginHarness(t, "/app")
+
+	m := th.LoadAndRunGenerator(`
+apiVersion: someteam.example.com/v1
+kind: GoGetter
+metadata:
+  name: example
+url: github.com/kustless/kustomize-examples.git?ref=9ca07d2
+subPath: dev
+command: kustomize build --enable_alpha_plugins
+`)
+
+	th.AssertActualEqualsExpected(m, `
+apiVersion: v1
+data:
+  altGreeting: Good Morning!
+  enableRisky: "false"
+kind: ConfigMap
+metadata:
+  name: dev-remote-cm
 `)
 }